Design in the chemical industry increasingly aims not only at economic but also at environmental targets. Environmental targets are usually best quantified using the standardized, holistic method of ...life cycle assessment (LCA). The resulting life cycle perspective poses a major challenge to chemical engineering design because the design scope is expanded to include process, product, and supply chain. Here, we first provide a brief tutorial highlighting key elements of LCA. Methods to fill data gaps in LCA are discussed, as capturing the full life cycle is data intensive. On this basis, we review recent methods for integrating LCA into the design of chemical processes, products, and supply chains. Whereas adding LCA as a posteriori tool for decision support can be regarded as established, the integration of LCA into the design process is an active field of research. We present recent advances and derive future challenges for LCA-based design.
•A hybrid damper is developed by combining a steel slit plate and friction pads.•Its effectiveness is investigated by cyclic test and by loss estimation.•The life cycle costs are computed based on ...FEMA P-58 methodology.•The hybrid damper turns out to be more effective than slit dampers with the same yield strength.
In this study a hybrid energy dissipation device is developed by combining a steel slit plate and friction pads to be used for seismic retrofit of structures, and its effectiveness is investigated by comparing the life cycle costs of the structure before and after the retrofit. A hybrid damper is manufactured and is tested under cyclic loading. It is observed that the damper shows stable hysteretic behavior throughout the loading history, and that the cumulative ductility ratio obtained from the experiment far exceeds the limit value required by the AISC Seismic Provisions. The probabilities of reaching various damage states are obtained by fragility analysis to evaluate the margin for safety against earthquakes, and the life cycle costs of the model structures are computed using the PACT (Performance Assessment Calculation Tool). According to the analysis results the slit-friction hybrid damper shows superior performance to the slit damper with the same yield strength for seismic retrofit of structures. The analysis results also show that the probabilities of reaching the limit states are minimized by the seismic retrofit with hybrid dampers combined with increasing column size. The combined seismic retrofit method also results in the lowest repair cost and shortest repair time.
Eukaryotic cells spend most of their life in interphase of the cell cycle. Understanding the rich diversity of metabolic and genomic regulation that occurs in interphase requires the demarcation of ...precise phase boundaries in situ. Here, we report the properties of two genetically encoded fluorescence sensors, Fucci(CA) and Fucci(SCA), which enable real-time monitoring of interphase and cell-cycle biology. We re-engineered the Cdt1-based sensor from the original Fucci system to respond to S phase-specific CUL4Ddb1-mediated ubiquitylation alone or in combination with SCFSkp2-mediated ubiquitylation. In cultured cells, Fucci(CA) produced a sharp triple color-distinct separation of G1, S, and G2, while Fucci(SCA) permitted a two-color readout of G1 and S/G2. Fucci(CA) applications included tracking the transient G1 phase of rapidly dividing mouse embryonic stem cells and identifying a window for UV-irradiation damage in S phase. These results show that Fucci(CA) is an essential tool for quantitative studies of interphase cell-cycle regulation.
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•Fucci(CA) is a genetically encoded optical sensor for live cell-cycle monitoring•The mechanism of Fucci(CA) requires S phase-specific CUL4Ddb1 ubiquitylation•Fucci(CA) demarcates interphase with boundaries between G1, S, and G2•Fucci(CA) visualized short G1 phases during rapid divisions of embryonic stem cells
Sakaue-Sawano et al. developed Fucci(CA), a genetically encoded optical sensor that monitors cell-cycle interphase. It employs an S phase-specific CUL4Ddb1-mediated ubiquitylation to sharply distinguish major cell-cycle transitions and phases, particularly G1, S, and G2. In the repertoire of Fucci probes, Fucci(CA) is ideal as an all-purpose, high-resolution interphase sensor.
Studies of Organisation for Economic Co-operation and Development (OECD) countries have generally failed to detect real economic expansions in preelection periods, casting doubt on the existence of ...opportunistic political business cycles. We develop a theory that predicts that a substantial portion of the economy experiences a real decline in the preelection period if the election is associated with sufficient policy uncertainty. In particular, policy uncertainty induces private actors to postpone investments with high costs of reversal. The resulting declines, which are called reverse electoral business cycles, require sufficient levels of polarization between major parties and electoral competitiveness. To test these predictions, we examine quarterly data on private fixed investment in ten OECD countries between 1975 and 2006. The results show that reverse electoral business cycles exist and as expected, depend on electoral competitiveness and partisan polarization. Moreover, simply by removing private fixed investment from gross domestic product, we uncover evidence of opportunistic cycles.
•A novel life-cycle reliability evaluation approach by synthesizing PDEM and the change of probability measure.•The new perspective of functionals by incorporating the Frobenius-Perron operator and ...the Radon-Nikodym operator.•An efficient algorithm by re-using the deterministic analyses.•Three examples showing the effectiveness of the proposed method.
Life-cycle time-variant reliability of engineering structures with material deterioration is of paramount importance but still a great challenge. Generally, the computational costs due to embedded structural analyses tracing the life-cycle performance process with monotonically deteriorating material, are prohibitively large. In the present paper, a new method by synthesizing the probability density evolution method (PDEM) and the change of probability measure (COM) is proposed for this purpose. Besides, a functional perspective is provided. The theoretical basis is established by involving the Frobenius-Perron operator, which characterizes the change of random variables, and the Radon-Nikodym operator, which characterizes the change of probability measure of the original source random variables. The material deterioration characterized by time-variant random variables can then be equivalently captured by the time-variant change of probability measure of the basic random variables. Thereby the deterministic analyses at different time instances can be shared in the process of capturing the time-variant probability density of the performance function, and thus the efficiency can be improved considerably. Numerical algorithms are elaborated. Three examples in terms of time-variant reliability evaluation of structures with monotonically deteriorating material and parametric stochastic loading are illustrated, showing the effectiveness of the proposed method. Problems to be further studied are also outlined.
Purpose
The Social Life Cycle Assessment guidelines (UNEP-SETAC
2009
) distinguish two different SLCA approaches, type I and type II. Few comprehensive and analytical reviews have been undertaken to ...examine the multiplicity of approaches that have been developed within type I SLCA. This paper takes on the task of exploring the evaluation methods used in type I SLCA methods.
Methods
In order to tackle this work, a critical literature review was undertaken, covering a total of 32 reviewed articles, ranging from 2006 to 2015. Those articles have been selected for they make explicit reference to type I, performance reference points (PRPs), corporate behavior assessment, and social performance assessment or if their assessment methods generated a result located at the same point as the inventory data, with regards to the impact pathway. The selected articles were analyzed with a focus on the inventory data used, the aggregation of inventory data on the functional unit, and the type of characterization and weighting methods used. This analysis allowed to make explicit the often implicit logic underlying the evaluation methods and to identify the common denominators of type I SLCA.
Results and discussion
The analysis highlighted the multiplicity of approaches that are comprised within type I SLCA today, both in terms of the data collected (in particular, its positioning along the impact pathway); the presence of some optional steps, such as the scaling of inventory data on the functional unit (FU); and in terms of the different characterization and weighting steps. With regards to data collection, this review has highlighted that the furthest indicators are positioned along the impact pathway, the hardest it is to justify the link between them and the activities of companies in the product system. The analysis also suggested that an important differentiating factor among type I SLCA methods lies in “what the inventory data is assessed against” at the characterization step and how it is ultimately weighted. To illustrate this, a typology of six characterization methods and five types of weighting methods was presented.
Conclusions
It is interesting to identify which approaches are most appropriate to respond to the various questions that SLCA aims to respond to. A question that arises is what approaches are most likely to tell us anything about the impact of a product system on social well-being? This question is particularly relevant in the absence of well-documented impact pathways between activities within product systems and impact on social well-being.
Life Cycle Sustainability Assessment (LCSA) in the built environment has increasingly drawn researchers’ attention in the preceding years; however, the lack of an integrated LCSA based model is still ...a barrier for its effective implementation into the building design process.
This paper proposes a new comprehensive LCSA model to be integrated into the design process of new buildings and energy refurbishment scenarios of existing ones. The proposed model consists of sets of mathematic equations to describe LCSA pillars of buildings, including Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and Social Life Cycle Assessment (SLCA) as the intermediate indices. A final LCSA index is then provided to describe a design scenario's performance from an LCSA perspective using the authors' new formulation and weighting method. The model is also integrated into the optimization process and enhanced with Machine Learning (ML) methods to accelerate the design-assessment process while preserving its accuracy. Finally, given the transition towards buildings' electrification by Renewable Energy Sources (RESs), as a supportive technology, the size-optimization of a residential building's short-term thermal and electrical Energy Storage Systems (ESSs) is chosen to demonstrate the model's capabilities. For this purpose, the building case study is parametrically modeled in Grasshopper, Energy plus, and Matlab for energy analysis, data processing, and machine learning.
•The existing challenges and research gaps in LCSA integration into the building design process are discussed.•A novel LCSA-Machine learning-based model is developed to optimize the design of sustainable buildings.•The model is applied in designing energy storage systems of a residential building as the case study.•The results show that the proposed model is highly accurate and efficient as a decision support system in the design process.•The case study resulted in 24.27 % reduction in electricity consumption and 9.94 % improvement in LCSA performance.
•A hybrid two–stage CO2 mechanical compression–ejector cooling cycle is studied.•A method for determination of the optimal design parameters of the proposed hybrid cooling cycle is ...presented.•Refrigerants R245ca, R601b and R1233zd(E) are used for the ejector cooling cycle.•The proposed hybrid cooling cycle is compared with conventional cooling cycle.•The improvements in energy efficiency reached up to 32.7%.
In the paper, the main results of thermodynamic analysis and optimization of the hybrid two–stage carbon dioxide (СО2) transcritical mechanical compression–ejector cooling cycle are presented. The proposed hybrid cooling cycle contains a two–stage CO2 transcritical mechanical compression refrigeration machine and an ejector cooling machine using refrigerants R245ca, R601b, and R1233zd(E). The operation of the ejector cooling cycle is ensured by using some part of the heat rejected from the compressed superheated CO2 vapor of the mechanical compression refrigeration cycle. The cold obtained in the ejector cooling machine is used for subcooling the high–pressure CO2 vapor after the gas cooler. In addition, the intermediate cooling of the CO2 vapor after the low–pressure stage of the mechanical compression refrigeration cycle is realized by preheating and boiling the refrigerant of the ejector cooling cycle in the additional generator–precooler before entering the main generator–precooler. This paper presents a method for determination of the optimal design parameters and performance of the proposed hybrid cooling cycle. The results showed an increase in efficiency of the two–stage CO2 transcritical mechanical compression refrigeration machine in the proposed cooling system of up to 32.7% compared to the conventional system at transcritical operating conditions with high an environmental temperature.
The hereditary cancer syndromes hereditary leiomyomatosis and renal cell cancer (HLRCC) and succinate dehydrogenase-related hereditary paraganglioma and pheochromocytoma (SDH PGL/PCC) are linked to ...germline loss-of-function mutations in genes encoding the Krebs cycle enzymes fumarate hydratase and succinate dehydrogenase, thus leading to elevated levels of fumarate and succinate, respectively
. Here, we report that fumarate and succinate both suppress the homologous recombination (HR) DNA-repair pathway required for the resolution of DNA double-strand breaks (DSBs) and for the maintenance of genomic integrity, thus rendering tumor cells vulnerable to synthetic-lethal targeting with poly(ADP)-ribose polymerase (PARP) inhibitors. These results identify HLRCC and SDH PGL/PCC as familial DNA-repair deficiency syndromes, providing a mechanistic basis to explain their cancer predisposition and suggesting a potentially therapeutic approach for advanced HLRCC and SDH PGL/PCC, both of which are incurable when metastatic.
Caproic acid is an emerging platform chemical with diverse applications. Recently, a novel biorefinery process, that is, chain elongation, was developed to convert mixed organic waste and ethanol ...into renewable caproic acids. In the coming years, this process may become commercialized, and continuing to improve on the basis of numerous ongoing technological and microbiological studies. This study aims to analyze the environmental performance of caproic acid production from mixed organic waste via chain elongation at this current, early stage of technological development. To this end, a life cycle assessment (LCA) was performed to evaluate the environmental impact of producing 1 kg caproic acid from organic waste via chain elongation, in both a lab-scale and a pilot-scale system. Two mixed organic waste were used as substrates: the organic fraction of municipal solid waste (OFMSW) and supermarket food waste (SFW). Ethanol use was found to be the dominant cause of environmental impact over the life cycle. Extraction solvent recovery was found to be a crucial uncertainty that may have a substantial influence on the life-cycle impacts. We recommend that future research and industrial producers focus on the reduction of ethanol use in chain elongation and improve the recovery efficiency of the extraction solvent.
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